Normally, you don't.
  You just enter and save the unique identifier (like a CustomerID), and
just display the address information that corresponds to that unique ID.
  A subform with address information fields from your Customer table...
linked to the main form by CustomerID will always display the address
information for the CustomerID you entered.
  No need to save all that address information on every new transaction
against a customer... you can always re-derive it on the fly from your
Customer table... in any subsequent query, form, or report
hth
Al Camp